72.go

package main

import (
	"fmt"
)

//给定两个单词 word1 和 word2，计算出将 word1 转换成 word2 所使用的最少操作数 。
//
//你可以对一个单词进行如下三种操作：
//
//插入一个字符
//删除一个字符
//替换一个字符
//示例 1:
//
//输入: word1 = "horse", word2 = "ros"
//输出: 3
//解释:
//horse -> rorse (将 'h' 替换为 'r')
//rorse -> rose (删除 'r')
//rose -> ros (删除 'e')
//示例 2:
//
//输入: word1 = "intention", word2 = "execution"
//输出: 5
//解释:
//intention -> inention (删除 't')
//inention -> enention (将 'i' 替换为 'e')
//enention -> exention (将 'n' 替换为 'x')
//exention -> exection (将 'n' 替换为 'c')
//exection -> execution (插入 'u')
//
//链接：https://leetcode-cn.com/problems/edit-distance

func main() {
	fmt.Println(minDistance("horse", "ros"))
}

func minDistance(word1 string, word2 string) int {
	word1Len, word2Len := len(word1), len(word2)
	if word1Len*word2Len == 0 {
		return word1Len + word2Len
	}

	dis := make([][]int, word1Len+1)
	for i := 0; i < word1Len+1; i++ {
		dis[i] = make([]int, word2Len+1)
	}
	for i := 0; i < word1Len+1; i++ {
		dis[i][0] = i
	}
	for j := 0; j < word2Len+1; j++ {
		dis[0][j] = j
	}

	for i := 1; i < word1Len+1; i++ {
		for j := 1; j < word2Len+1; j++ {
			if word1[i-1] == word2[j-1] {
				dis[i][j] = min(min(dis[i-1][j], dis[i][j-1]), dis[i-1][j-1]-1) + 1
			} else {
				dis[i][j] = min(min(dis[i-1][j], dis[i][j-1]), dis[i-1][j-1]) + 1
			}
		}
	}
	return dis[word1Len][word2Len]
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}